Inductance system



INDUCTANCE SYSTEM Filed.June 5, 1929 2 Sheets-Sheet 2 TEF.. 5

INVENTOR.

A TToRNEY Patented June 16, 1931 UNITED STATES PATENT oFElcE LOUISr A. GEBHARD, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGv-NOR TO WIRED RADIO, INC., OF NEW YORK, N. Y., A CORPORATION OF DELAWARE Y INnUcTANcE SYSTEM Application led June 5, 1929. Serial No. 368,691.

My invention relates broadly to inductance systemsv and more particularly to inductance systems employed in high frequency transmitters.

One of the objects of my invention is to provide an' eflicient adjustable inductance system. Y

Another object ofmy invention is to pro'- vide a plurality of interchangeable inducln tances adapted to be selectively placed in election of the inductance system of my inven-y tionf; Fig. 2 shows a part horizontal section of the inductance system of my invention on line-2-2of Fig. 1 ,F ig. 3 shows a side elevation of a modification of my invention; Fig. 4 shows a part horizontal section of the modiiedA form of my invention on line Y 4 4 of Fig. 3; and Fig. 5 shows an end view of a section of theinductance system of my invention on line 5 5 of Fig. 3. Y

In highy frequency transmitters it is necessary to'employ inductances to control'theV frequency of the generated energy. Vhen ultra highv frequency isl employed the inductance must be of a low order. This limits the physical dimensions. As the physical dimensions are limited the safe current carrying capacity is limited. In the adjustable inductance system of my invention large values of current may be safely carried without employing an inductance of large physical dimensions. When 'employing adjustable inductances it is essential that the losses be reduced to a minimum. Losses resulting from unused portions of. an inductance coil and induction between the used and unused coils are avoided in the inductance system of my invention.

Figs. 1 and 2 of the drawings show a side elevation and a part section respectively of one form of the inductance system of my invention. To prevent excessive rise of temperature when the inductance system is employed in high power transmitters, I employ a cooling system which adequately lmaintains the inductance coils at a normal temperature.

Inductance coils 1, 2, 3 and 4 are mounted on insulating supports 5. Coils 1, 2, 3 and 4 comprise lengths of metallic tubing or the like wound in the helical formation illustrated. Contacts 6 are carried by each of the coils by means of which electrical connection to an external circuit is established when the respective coils are in the proper position and contacts 6 engage with brush contacts 7. Brush contacts 7 may Vbe of any suitable spring metal vmounted on an insulating bar 8. Brush contacts 7 are adapted to be adj ustably positioned on bar 8 in the proper positions whereby contact will be established with the respective contact members 6 carried by coils 1, 2, 3 and 4. Coils 1, 2, 3 and 4 are of increasing inductance value in the order named. Coils 1, 2, 3 and 4 interconnectedby means of lengths of insulating tubing 9. Insulating tubing` coils 10 and 11 are wound around forms 12 and 13 respectively and provide a high resistance path for direct current. The iluid circulates through insulating tubing coil 11, coil 4, coil 3, coil 2, coil 1 and insulating tubing coil 10 or in reverse of the order named. The circulation is continuous through the entire inductance system. Insulating members 5, 12 and 13 mountedl on tubes 14 and 15 form a part of thesupporting framework for each of the coils. Tubes 14 and 15 are of slightly larger diameters than tubes 16 and 17, the former sliding over the latter and affording liquid tight connections for the circulating fluid. The upper ends of tubes 14 and 15 connect to the ends of insulating coils 11 and 10, respectively.

The cooling fluid may be admitted to the lower end of tube 16 and caused to circulate through insulating` coil lll, through metallic inductance coils 4f, El, 2 and l, throurh insu latinl coil l0, through tube l5 and out of the indnctance system through tube 1T. The 'franieworli carryingnY coils l, 2, 3 and el. may be moved in the vertical plane select connecting the respective coils with external circuits. A suitable mechanical arrangement for effecting this movement shown and tully described in my (fo-pending application Serial No. 400,082 tiled October 16, i928. The selected inductance coil tor a given lirequency adjustment may be retained in contact with the external circuit by ineens o1? stops 21A inserted in holeeV4 Holes l@ are provided in vertical trame members 21a Members 2l@ are supported by horizontally positioned members 2l?) and 21.0.

Figs. 3, l and illustrate liront. sectional and side elevations, resjiectively7 or" a modilication ot the adjustable inductance system ot my invention. leieience characters correspond to those shown in Fics l and EX- teusions o'tl insulating tubing; coils l() and ll are shown compra-zing liexible loops at the points i9 andv lll rcspcctively7 ivhcn the coil system is moved in a vertical plane. Monibers 22 serve to guide the tub lo; from the framework, and are carried by member 2f). Flupportingl members 5, l2 and ,l-3 are oi suntablo ineulating` material and are positioned on the verticalinsnlating members 23 and Oft. The fiameworl@ carrying; coils l, E2, 3 and and insulating; tubing coils l0 and 'll niej be adjusted in the vertical plane without in terrupting the circulation oi' the cooling' fluid.

Under most operating conditions it is essential that coils 'l7 2, 3 and 4 be electrically insulated trom each other. The coupling: units interconnecting` the several coils may therefore comprise lengths ot rubber tuliiug` or the like which will serve the purpose.

Many modifications o'i" my invention possible without departing` 1from the spirit o'l my invention. l have referred to the movement ot' the indnctancc coils in a vertical plane. llov/evcr. it is obvionsii that the traineworl; may be positioned in a horizontal plane it desired and the movement ot the coils groverned accordingly. In radio transmitters in locations where space very limited as on shinboarrb it is necessary to use every cubic inch ot space to the 4greatest possible advantage. The indnctance system ot my invention is inherently compact and very advantageous tor such locations. In other systems the electromagnetic induction between used and. unused coils introduces serions losses. This etten occurs where the distance ot movement necessary lo atleet chance ot coils is greater than the distance between the axes ot tlie coils. In the indnctance system ot my invention the distance between the aries ot the several coils employed is the same as the distance traversed to effect a change of coils.

Thus assume a drum type of variable in'- dnctance system, having' tour cylindrical inductances symmetrically mounted on a cylindrical 'frame with their axes parallel to the axis oi the cylindrical :trame and having contact elements projecting` at their outermost points. The distance between the contact elements oit adjacent iinluctaiices will be equal to a quadrant ot the peripheral circle oi` the cylindrical 'tramework7 and `in practice the shortest distance between adjacent inductances will be less than halt the 'adius ot the cylindrical traine. It now it be assumed that the same two coils are mounted on a ladder or linear 'traine with the same distance as be- 'iore between the contac` elements of adjacent coils. the shortest dis'ance between adjacent coils will in practice be found to be twice or more as large as with the drum type. The interaction between adjacent coils increases rapidly as the shortest distance between adjacent coils is reduced and hence the ladder tyife has inherent advantages over th e drum typo because ot the reduced interaction.

l reali'fze that inany modifications ot in v iilvention are possiliile and it is to be understood that the embodiments of my invention are not to be restricted by the foregoing` specilication or by the accompanyiugl drawings but only by such restrictions as are imposed by the appended claims.

fluit ,l claim as new and desire to secure by Letters Patent ot the United States is as follows:

l. Au adjustable influcta nce system coniprisinej a fined framework, a racl: trameworl: movable with respect to said l'iied 'trmneworlf1 a plurality ot individual inductance coils, pos-:itioncd ou said racl 'tramework` fixed contact elements carried by said lifted iran'iewfn-lc, said coils comprising lengths ot metallic tnbinn adapted to be cooled by a circulating lluid, cach ol said coils beineI provided with coil contact elements adapted to engage said fixed intact elements selectively. and said 'racky 'tra iuework adapted to be adjusted to d iii tereut positions whereby said coils are selcw tively connected with au external circuit.

f2. An adjustable indnctance system com- @risingl in combination a fined iraiueworlt. a rack irainewirlt movable with respect to said fired iraineworlc a plurality ot individual inductance coils spacially positioned along said rack trauicwoil:n [ined contact elements car-- ried` by said fixed 'lianiewoi-lc. said coils comprision; individual lengths oi metallic tubing; physically interconnected for the circulation ot a cooling); fluid and electrically insulated from each otherf, coil contacts carried by each oi" said coils and adapted to selectively cnjafre said lined contact elements as said 'ti-:nucworll: is moved. whereby said coils are selectively connected with an external circuit.

3. Au adjustable inductance system comprising;l in combination a movable rack mem ber a plurality of inductance coils each having different frequency characteristics, said coils being spacially positioned on said movable rack member, said coils comprising individual lengths of metallic tubing interconnected by fluid conducting electrical insulating members for the circulation of a cooling fluid and adapted to be selectively connected with an external circuit.'

4. An adjustable inductance system comprising in combination a plurality of helically wound inductance coils of different frequency characteristics disposed in the same-plane and adapted to carry large currents, said inductance coils being carriedl by a movable rack and having an interior channel through which cooling circulatory liquid flows. j

5. An adjustable inductance system comprising in combination a plurality of inductance coils having their axes extending parallel one to another and having different frequency characteristics being positioned on a movable rack member and in substantially the same plane, said coils comprising lengths of helically wound tubing and being physically interconnected for the Vcirculation of a cooling fluid.

6. An adjustable inductanceisystem com-v prising in combination a plurality of inductance coils specially positioned with their axes in substantially the same plane and spaced one from another on a movable rack member, said coils having fluid conducting passages and said coils vbeing physically interconnected by fluid conducting members.

7. An adjustable inductance system comprising in combination a plurality of independent electrical inductance coils, said coils comprising lengths of helicaliy wound tubing interconnected by fluid conducting members, a rack framework carrying said coils and adapted to be adjusted in a given plane, and means for selectively effecting electrical connection between said coils and an external circuit. f

8. Au adjustable inductance system comprising in combination a :fixed framework, a rack framework movable with respect to said fixed framework, fixed contact membersV carried by said fixed framework a plurality of helically wound inductance coils spacially positioned on said rack framework, said coils comprising individual lengths of metallic tubing interconnected for the circulation of a cooling fluid therethrough, independent contact members carried by said coils and means for moving said rack whereby the independent contact members on said coils are selectively connected with the fixed contact members on said framework and with an external circuit.

9. An inductance system of the ladder type, comprising a fixed frame member, a movable frame member adjustable in position with respect to said fixed frame member, a

plurality of lateralco-p'lanar members carried'y by `said adjustable frame member, a plu` rality ofhelical'ly wound tubular inductance with respect to said .fixed frame member, a,

plurality of lateral `co-planar members carried by said adjustable frame member, a plurality of lielically wound tubular inductance elements carried respectively by said lateral members, said inductance elements being connected in electrical insulating relation for the continuous passage of liquid successively therethrough, flexible electrically insulating liquid conductors connecting the unconnected ends of the terminal inductance elements respectively to a source of fluid supply and a waste discharge, fixed contacty elements Acarried by said fixed frame, and coil contact elements carried respectively by said coils and adapted to engage said fixed contact elements as the vposition of said vadjustable frame is changed. y

11. An inductance system of the ladder type comprising a fixed frame member, a' movable frame member adjustable in position with respect to said fixed frame member, a pluralityv of lateral co-planar members carried by said Vadjustable frame member, a plurality of helically wound tubular inductance elements having different values of'inductance carried respectively by said lateral members, said inductance elements being connected in electrical insulating relation for the continuous passage of liquid successively therethrough, fixed contact elements carried by said fixed frame, and'coil,`

contact elements carried respectively by said coils and adapted to engage said fixed contact elements as the position of said adjustable frame is changed.

l2. An inductance system of the ladder type comprising a pair of fixed tubular members, a pair of movable tubular members adapted to respectively telescope over said fixed tubular members in water-tight relation, a plurality of lateral members extending between said movable tubular members, a plurality of helically wound tubular inductance elements carried respectively by said lateral members, said indue-tance elements being connected in electrical insulating relation for the continuous passa-ge of liquidv successively therethrough, fluid conductors connecting the unconnected ends of the terminzrl nduetanee elements respectively to said movable tubular members for the passage of fluid therethrough, a Source for supplying cooling liquid to one of said tubular members, means for conduct-mg Waste liquid from one of said tubular members, lzied Contact elements ezufred by said, xed tubular members7 md co Contact elements Carried respectively by Seid Coils and adapted to e11- gage seid fixed Contact elements as the postion of seid movable iubular members is changed.

LOUIS A. GERHARD.

CERTIFICATE OF CORRECTION.

Patent No. 1,809,933. Granted June 16, 1931, to

LOUIS A. GEBHARD.

It is hereby certified that error appears in. the. printed specification of the above numbered patent requiring correction as foilows: Page 3, line 30, claim 6, for the word "specially" read spacally; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 14th day of July, A. D. 1931.

M. J. Moore, (Seal) Acting Commissioner of Patents.

CERTIFICATE F CORRECTION.

Patent No. 1,809,933. Granted. June i6, 1931, to

LOUIS A. GERHARD.

It is hereby certified that error appears in4 the printed spociiication of the above numbered patent requiring correction as foi lows: Page 3, lino 30, claim 6, for the word "specially" road spaciaiiy; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the caso in the Patent Office.

Signed and sealed this 14th day of July, A. D. 1931.

M. J. Moore, (Seal) Acting Commissioner of Patents. 

